Molecular imaging of gene expression in vivo, in real time and at the cellular level is a rapidly growing area of medical research that will provide insight into the origin and progression of disease at the genetic level. Instrumentation for non-invasive longitudinal monitoring of disease progression, cell trafficking and gene expression patterns in life animals are now available. This modality will provide insights not previously possible with classical histopathology techniques. The Xenogen Corporation's IVIS in vivo bioluminescence imaging system is recognized as being at the forefront of this emerging field. We have been operating such a system for the past four years as a shared research facility under the name In-Vivo Molecular Imaging Lab (IMIL). The current system which is a Xenogen IVIS 200 was purchased in late 2005 using contributions from 12 department chairs funds and matching contributions from the dean of the medical school. During this time we have had a very smooth and successful operation and have supported many departments resulting in grants and papers. Although state of the art at the time of purchase, this technology has advanced in recent times. In this application we are seeking to apply for funds for an upgrade to the next generation system from the same company. The new system is called Spectrum. This new system is the latest in this modality with improved resolution as well as more filters for imaging of additional optical wavelengths. The Spectrum can be purchased as a new unit, but our current IVIS 200 has an upgrade path that allows us to obtain the Spectrum at a fraction of the cost. Public Health Relevance: Animal models of disease are essential in medical research. Bioluminescent imaging allows researchers with small animal models of disease to monitor in-vivo disease progression and cellular function.